Wireless wide-area communication networks are being proposed using multihop relay stations, such as that proposed for WiMAX networks, i.e. IEEE 802.16j. Such networks provide for the automatic transfer of wireless communication between a base station (access point) and a mobile station (terminal) using intermediate relay stations. It follows that there is a demand for an apparatus a method for automating a seamless transfer of such wireless communication.
Of course, it is presently known how to operate base stations and mobile stations in direct communication. But one of the problems encountered when performing a mobile multihop relay (MMR) wireless communication in a wireless Wide Area Network (WAN) is the lack of an optimal mechanism for managing the operation of the relay stations. For example, relay stations may be active or inactive, and it needs to be determined how to manage these relay stations during communication origination, termination, re-establishment, and handoff.
An active relay station (RS) with an active mobile station (MS) associated therewith can be viewed similarly to a base station (BS), and typical BS-to-BS handoff and MS origination, termination, and re-establishment algorithms can be re-used with slight modifications. However, there are technical challenges in when to inform the MS to handoff from a BS to an inactive RS, and how to turn on an inactive RS to assist the MS in call origination, termination, and re-establishment. In addition, channel quality estimation for both uplink (UL) and downlink (DL) channels between the MS and RS presents difficulties. For example, all DL related triggers cannot be used since an inactive RS will not be transmitting preamble or pilot bits, and the MS cannot report the DL channel quality between itself and an inactive RS. Moreover, base station neighbor lists would not include an inactive RS.
What is needed is an apparatus and method for managing a relay station, and particularly an inactive relay station, in a wireless WAN communication system.